SIBCOLOR HYBRIDSTetraploid hybrids between tetraploid Sibiricas(4n=56) and forms of Iris versicolor(2n=72 to 108). These hybrids, the first of which was obtained by the German Artur Winkelmann, are only slightly fertile. The fact that they can be produced, promotes the theory that Iris versicolor is a natural tetraploid (amphidiploid) with two chromosome sets each from Iris setosa interior and Iris virginica shrevei. - Sibcolor hybrids so far have a limited colour range, but they are robust and broad leaved garden plants.